Hierarchical analysis of amphibian diversity in primary and secondary rain forests of central Vietnam

We assessed species composition, diversity, and distribution patterns of rain forest amphibian assemblages in central Vietnam using a hierarchical analysis of diversity across study areas and different habitat types. We also plotted rarefaction curves to compare unequal assemblages of amphibians and compared the results with our field observations. We recorded 13,529 individuals of 100 species from Anura and Gymnophiona, comprising eight families and 33 genera. There was an overall similarity in species composition of 0.86 between two areas, A Luoi and Nam Dong, Thua Thien Hue Province, central Vietnam; however, the overall similarity in species composition between primary and secondary forests was only 0.03. Only 29 species (29%) of total recorded amphibians were found in both forest types. The relative abundance and species richness were significantly higher in primary forests than in secondary forests. In both areas, rarefaction curves revealed that the expected number of amphibian species in primary forests was significantly richer than that in secondary forests, suggesting that assemblages of amphibians in interior forest habitat may be more vulnerable to alterations caused by disturbances, such as logging. The lognormal model to predict the expected total number of species theoretically available for observation in the entire community (including the rare species not yet collected) indicated that the expected total number of species is approximately 105, with the number of unseen species predicted to fall below the veil line estimated at about 4.48.